1. Field of the Invention
This invention relates to a method of catalytically converting olefins into gasoline fractions, particularly by passing olefins over a ZSM-5 type zeolite having reduced aromatization activity.
2. Brief Description of the Prior Art
It has long been known to contact various hydrocarbon fractions with acidic catalysts generally and, in particular, with solid siliceous acidic catalysts -- including those referred to as crystalline aluminosilicate zeolites. Contact of said hydrocarbon feed with said acid catalysts was carried out for a wide variety of reactions including cracking, isomerization, hydrocracking, etc. Representative U.S. patents disclosing and claiming contacting of various hydrocarbon fractions with crystalline aluminosilicates are U.S. Pat. No. 3,140,249; 3,140,251; 3,140,253; and 3,140,322.
The contact of paraffinic feedstocks with crystalline aluminosilicate zeolites is also known in the art and by far the primary reason for contacting paraffinic materials with zeolites has been for the purpose of cracking them, i.e. converting then to lower molecular weight products. Typical applications in this general field would be the use of crystalline aluminosilicate zeolites for carrying out dewaxing reactions, i.e. the cracking of paraffins to low molecular weight materials. U.S. Pat. No. 3,400,072 discloses a dewaxing process with crystalline aluminosilicates generally and copending application Ser. No. 865,470, filed Oct. 10, 1969, now U.S. Pat. No. 3,700,585, discloses and claims dewaxing operations carried out with a novel type of crystalline aluminosilicates identified as those of the ZSM-5 type.
The instant application is not concerned with hydrocarbon conversion in general, but rather, is concerned with the conversion of a hydrocarbon feed consisting essentially of C.sub.2 -C.sub.5 olefins, mixtures thereof and mixtures thereof with paraffins. Additionally, the instant application is not concerned primarily with the cracking of these materials to still lower molecular weight products, but rather, is concerned primarily with the preparation of higher molecular weight olefins from the stated feed.